U.S. patent number 10,913,754 [Application Number 16/251,236] was granted by the patent office on 2021-02-09 for lanthanum compound and methods of forming thin film and integrated circuit device using the lanthanum compound.
This patent grant is currently assigned to ADEKA CORPORATION, SAMSUNG ELECTRONICS CO., LTD.. The grantee listed for this patent is SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Youn-joung Cho, Kazuki Harano, Youn-soo Kim, Jae-soon Lim, Gyu-hee Park, Haruyoshi Sato, Tsubasa Shiratori, Naoki Yamada.
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United States Patent |
10,913,754 |
Park , et al. |
February 9, 2021 |
Lanthanum compound and methods of forming thin film and integrated
circuit device using the lanthanum compound
Abstract
A lanthanum compound, a method of synthesizing a thin film, and
a method of manufacturing an integrated circuit device, the
compound being represented by Formula 1 below, ##STR00001##
wherein, in Formula 1, R.sup.1 is a hydrogen atom or a C1-C4 linear
or branched alkyl group, R.sup.2 and R.sup.3 are each independently
a hydrogen atom or a C1-C5 linear or branched alkyl group, at least
one of R.sup.2 and R.sup.3 being a C3-C5 branched alkyl group, and
R.sup.4 is a hydrogen atom or a C1-C4 linear or branched alkyl
group.
Inventors: |
Park; Gyu-hee (Hwaseong-si,
KR), Kim; Youn-soo (Yongin-si, KR), Lim;
Jae-soon (Seoul, KR), Cho; Youn-joung
(Hwaseong-si, KR), Harano; Kazuki (Tokyo,
JP), Sato; Haruyoshi (Tokyo, JP),
Shiratori; Tsubasa (Tokyo, JP), Yamada; Naoki
(Tokyo, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG ELECTRONICS CO., LTD. |
Suwon-si |
N/A |
KR |
|
|
Assignee: |
SAMSUNG ELECTRONICS CO., LTD.
(Suwon-si, KR)
ADEKA CORPORATION (Tokyo, JP)
|
Family
ID: |
1000005350162 |
Appl.
No.: |
16/251,236 |
Filed: |
January 18, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190152996 A1 |
May 23, 2019 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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15092953 |
Apr 7, 2016 |
10329312 |
|
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Foreign Application Priority Data
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Jul 7, 2015 [KR] |
|
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10-2015-0096785 |
Mar 16, 2018 [KR] |
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10-2018-0031127 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L
21/0228 (20130101); H01L 21/02192 (20130101); C23C
16/405 (20130101); H01L 27/281 (20130101); C23C
16/34 (20130101); H01L 51/001 (20130101); C07F
5/00 (20130101); H01L 51/0026 (20130101); C23C
16/45553 (20130101); H01L 51/0512 (20130101); H01L
51/0089 (20130101); H01L 29/785 (20130101); H01L
29/66795 (20130101) |
Current International
Class: |
C07F
5/00 (20060101); C23C 16/40 (20060101); C23C
16/455 (20060101); C23C 16/34 (20060101); H01L
27/28 (20060101); H01L 21/02 (20060101); H01L
51/00 (20060101); H01L 29/78 (20060101); H01L
29/66 (20060101); H01L 51/05 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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101792469 |
|
Aug 2010 |
|
CN |
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102057077 |
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May 2011 |
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CN |
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2391555 |
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Feb 2004 |
|
GB |
|
2011514433 |
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May 2011 |
|
JP |
|
2011522833 |
|
Aug 2011 |
|
JP |
|
10-0590051 |
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Jun 2006 |
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KR |
|
10-0684992 |
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Feb 2007 |
|
KR |
|
10-2017-0006205 |
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Jan 2017 |
|
KR |
|
200938653 |
|
Sep 2009 |
|
TW |
|
201002855 |
|
Jan 2020 |
|
TW |
|
WO 2004/046417 |
|
Jun 2004 |
|
WO |
|
WO 2007/129670 |
|
Nov 2007 |
|
WO |
|
Other References
Office action dated Aug. 1, 2019 in the corresponding Chinese
Application No. 201610529169.5. cited by applicant .
Taiwanese Notice of Allowance dated Nov. 26, 2019 for corresponding
application TW 105121474. cited by applicant .
C.K. Chiang, et al., "Effects of La.sub.2O.sub.3 Capping Layers
Prepared by Different ALD Lanthanum Precursors on Flatband Voltage
Tuning and EOT Scaling in TiN/HfO.sub.2/SiO.sub.2/Si MOS
Structures", Journal of the Electrochemical Society, 158 (4),
H447-H451, 2011. cited by applicant.
|
Primary Examiner: Brooks; Clinton A
Attorney, Agent or Firm: Lee IP Law, P.C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of U.S. patent
application Ser. No. 15/092,953, filed on Apr. 7, 2016, entitled
"Lanthanum Compound, Method of Synthesizing Lanthanum Compound,
Lanthanum Precursor Composition, Method of Forming Thin Film, and
Method of Manufacturing Integrated Circuit Device," which is hereby
incorporated by reference in its entirety.
Korean Patent Application No. 10-2018-0031127, filed on Mar. 16,
2018, in the Korean Intellectual Property Office, and entitled:
"Lanthanum Compound, and Methods of Forming Thin Film and
Integrated Circuit Device Using the Lanthanum Compound," and Korean
Patent Application No. 10-2015-0096785, filed on Jul. 7, 2015, in
the Korean Intellectual Property Office, and entitled: "Lanthanum
Compound, Method of Synthesizing Lanthanum Compound, Lanthanum
Precursor Composition, Method of Forming Thin Film, and Method of
Manufacturing Integrated Circuit Device," are incorporated by
reference herein in their entirety.
Claims
What is claimed is:
1. A lanthanum compound represented by Formula 1 below,
##STR00013## wherein, in Formula 1, R.sup.1 is a hydrogen atom or a
C1-C4 linear or branched alkyl group, R.sup.2 and R.sup.3 are each
independently a hydrogen atom or a C1-C5 linear or branched alkyl
group, at least one of R.sup.2 and R.sup.3 being a C3-C5 branched
alkyl group, and R.sup.4 is a hydrogen atom or a C1-C4 linear or
branched alkyl group, wherein the compound is an asymmetrical
amidinate in which R1 and R.sup.3 are substituents having different
structures from each other.
2. The lanthanum compound as claimed in claim 1, wherein: one of
R.sup.2 and R.sup.3 is a C3-C5 branched alkyl group, and the other
one of R.sup.2 and R.sup.3 is a C1-C5 linear alkyl group.
3. The lanthanum compound as claimed in claim 1, wherein: one of
R.sup.2 and R.sup.3 is an iPr group, an iBu group, a tBu group, or
an sBu group, and the other one of R.sup.2 and R.sup.3 is a Me
group, an Et group, an nPr group, or an nBu group.
4. The lanthanum compound as claimed in claim 3, wherein: R.sup.1
is hydrogen atom, a Me group, an Et group, an nPr group, or an iPr
group, and R.sup.4 is a Me group, an Et group, an nPr group, or an
iPr group.
5. The lanthanum compound as claimed in claim 1, wherein the
lanthanum compound has a structure represented by one of Chemical
Formulae 1 to 4, ##STR00014##
6. The lanthanum compound as claimed in claim 1, wherein the
lanthanum compound is a liquid at a temperature between 20.degree.
C. to 28.degree. C.
7. A method of synthesizing a thin film, the method comprising
forming a lanthanum-containing film on a substrate by using the
lanthanum compound as claimed in claim 1, which is a liquid at a
temperature between 20.degree. C. to 28.degree. C.
8. The method as claimed in claim 7, wherein forming the
lanthanum-containing film includes: vaporizing the lanthanum
compound represented by Formula 1 in which one of R.sup.2 and
R.sup.3 is a C3-C5 branched alkyl group, and the other one of
R.sup.2 and R.sup.3 is a C1-C5 linear alkyl group; forming a La
source adsorption layer on the substrate by supplying the vaporized
lanthanum compound onto the substrate; and supplying a reactive gas
onto the La source adsorption layer.
9. The method as claimed in claim 7, wherein forming the
lanthanum-containing film includes: vaporizing the lanthanum
compound represented by Formula 1, in which R.sup.2 and R.sup.3 are
each independently a C3-C5 branched alkyl group, and R.sup.4 is a
C2-C4 linear or branched alkyl group; forming a La source
adsorption layer on the substrate by supplying the vaporized
lanthanum compound onto the substrate; and supplying a reactive gas
onto the La source adsorption layer.
10. A method of manufacturing an integrated circuit device, the
method comprising: forming a lower structure on a substrate; and
forming a lanthanum-containing film on the lower structure by using
the lanthanum compound as claimed in claim 1, and which is a liquid
at 20.degree. C. to 28.degree. C.
11. The method as claimed in claim 10, wherein forming the
lanthanum-containing film includes using the lanthanum compound
represented by Formula 1, in which, in Formula 1, one of R.sup.2
and R.sup.3 is a C3-C5 branched alkyl group and the other one of
R.sup.2 and R.sup.3 is a C1-C5 linear alkyl group.
12. The method as claimed in claim 10, further comprising diffusing
La atoms into a region of the lower structure from the
lanthanum-containing film by heat-treating the lanthanum-containing
film.
13. The method as claimed in claim 10, wherein forming the lower
structure includes: forming fin-type active region protruding
upwardly from the substrate by etching a portion of the substrate;
forming an interface layer on surface of the fin-type active
region; and forming a high-k dielectric film on the interface
layer, wherein forming the lanthanum-containing film includes
forming the lanthanum-containing film on the high-k dielectric
film.
14. The method as claimed in claim 13, further comprising diffusing
La atoms into an interface between the interface layer and the
high-k dielectric film by heat-treating the lanthanum-containing
film.
15. The method as claimed in claim 10, wherein forming the lower
structure includes: forming gate trench in the substrate; forming a
gate dielectric film covering inner surface of the gate trench; and
forming a gate line that fills a portion of the gate trench on the
gate dielectric film, the gate line including a metal-containing
liner covering the gate dielectric film and a metal film surrounded
by the metal-containing liner, wherein forming the
lanthanum-containing film includes forming the lanthanum-containing
film on the metal-containing liner, and wherein the method further
includes forming a La doped metal-containing liner on a portion of
an upper region of the metal-containing liner by diffusing La atoms
into the metal-containing liner from the lanthanum-containing film,
after forming the lanthanum-containing film.
Description
BACKGROUND
1. Field
Embodiments relate to a lanthanum compound, and a method of forming
a thin film and an integrated circuit device by using the lanthanum
compound.
2. Description of the Related Art
With the development of electronic technology, semiconductor
devices have been rapidly down-scaled. Accordingly, patterns
constituting an electronic device have been miniaturized. Also,
various studies have been conducted about integrated circuit
devices providing high operation speed and high reliability.
SUMMARY
The embodiments may be realized by providing a lanthanum compound
represented by Formula 1 below,
##STR00002##
wherein, in Formula 1, R.sup.1 is a hydrogen atom or a C1-C4 linear
or branched alkyl group, R.sup.2 and R.sup.3 are each independently
a hydrogen atom or a C1-C5 linear or branched alkyl group, at least
one of R.sup.2 and R.sup.3 being a C3-C5 branched alkyl group, and
R.sup.4 is a hydrogen atom or a C1-C4 linear or branched alkyl
group.
The embodiments may be realized by providing a method of
synthesizing a thin film, the method including forming a
lanthanum-containing film on a substrate by using a lanthanum
compound that is a liquid at a temperature between 20.degree. C. to
28.degree. C., wherein the lanthanum compound is represented by
Formula 1, below,
##STR00003##
wherein, in Formula 1, R.sup.1 is a hydrogen atom or a C1-C4 linear
or branched alkyl group, R.sup.2 and R.sup.3 are each independently
a hydrogen atom or a C1-C5 linear or branched alkyl group, at least
one of R.sup.2 and R.sup.3 being a C3-C5 branched alkyl group, and
R.sup.4 is a hydrogen atom or a C1-C4 linear or branched alkyl
group.
The embodiments may be realized by providing a method of
manufacturing an integrated circuit device, the method including
forming a lower structure on a substrate; and forming a
lanthanum-containing film on the lower structure by using a
lanthanum compound represented by Formula 1 below, and which is a
liquid at 20.degree. C. to 28.degree. C.,
##STR00004##
wherein, in Formula 1, R.sup.1 is a hydrogen atom or a C1-C4 linear
or branched alkyl group, R.sup.2 and R.sup.3 are each independently
a hydrogen atom or a C1-C5 linear or branched alkyl group, at least
one of R.sup.2 and R.sup.3 being a C3-C5 branched alkyl group, and
R.sup.4 is a hydrogen atom or a C1-C4 linear or branched alkyl
group.
BRIEF DESCRIPTION OF THE DRAWINGS
Features will be apparent to those of skill in the art by
describing in detail exemplary embodiments with reference to the
attached drawings in which:
FIG. 1 illustrates a flowchart of a method of forming a thin film,
according to embodiments;
FIG. 2 illustrates a flowchart of a method of forming a lanthanum
oxide film, according to embodiments;
FIGS. 3 through 6 illustrate schematic configurations of example
deposition devices that may be used in a process of forming a thin
film according to embodiments;
FIG. 7 illustrates a graph of a TG-DTA analysis result of a
lanthanum compound according to an embodiment;
FIG. 8 illustrates a graph of a differential scanning calorimetry
(DSC) analysis result of a lanthanum compound according to an
embodiment;
FIG. 9 illustrates a graph of a TG-DTA analysis result of a
lanthanum compound according to another embodiment;
FIG. 10 illustrates a graph of a DSC analysis result of a lanthanum
compound according to another embodiment;
FIG. 11 illustrates a graph of a TG-DTA analysis result of a
lanthanum compound according to another embodiment;
FIG. 12 illustrates a graph of a DSC analysis result of a lanthanum
compound according to another embodiment;
FIG. 13 illustrates a graph of a deposition rate relative to a
deposition temperature in a process of forming a lanthanum oxide
film by using a method of forming a thin film according to an
embodiment;
FIG. 14 illustrates a graph of a result of an X-ray fluorescence
(XRF) relative to a deposition cycle in a process of forming a
lanthanum oxide film by using the method of forming a thin film
according to an embodiment;
FIG. 15 illustrates a perspective view of an integrated circuit
device according to an embodiment;
FIGS. 16A through 16G illustrate cross-sectional views of stages in
a method of manufacturing an integrated circuit device according to
an embodiment;
FIG. 17 illustrates an equivalent circuit diagram of an integrated
circuit device according to another embodiment;
FIG. 18 illustrates a cross-sectional view of a partial
configuration of an example non-volatile memory device that may
configure a memory cell array of the example integrated circuit
device of FIG. 17;
FIG. 19 illustrates a plan layout of key constituent elements of an
integrated circuit device according to another embodiment; and
FIGS. 20A through 20G illustrate cross-sectional views of stages in
a method of manufacturing an integrated circuit device according to
another embodiment.
DETAILED DESCRIPTION
The term "substrate" used herein may denote the substrate itself or
a stacking structure including the substrate and a predetermined
layer or a film formed on a surface of the substrate. Also, the
term "a surface of a substrate" used herein may denote either an
exposed surface of the substrate itself or an external surface of a
predetermined layer or a film formed on the substrate.
In the present specification, the term "Me" indicates a methyl
group, the term "Et" indicates an ethyl group, the term "Pr"
indicates a propyl group, the term "nPr" indicates a normal propyl
group or a linear propyl group, the term "iPr" indicates an
isopropyl group, the term "Bu" indicates a butyl group, the term
"nBu" indicates a normal butyl group or a linear butyl group, the
term "tBu" indicates a tert-butyl group (1,1-dimethyl ethyl group),
the term "sBu" indicates a sec-butyl group (1-methyl propyl group),
and the term "iBu" indicates an iso-butyl group (2-methyl propyl
group).
The term "room temperature" used herein may denote a temperature in
a range of about 20.degree. C. to about 28.degree. C., e.g., it may
vary according to seasons.
A lanthanum compound according to an embodiment may have an
amidinate ligand. In an implementation, at least one of two
nitrogen atoms that constitute the amidinate ligand may have a
branch type structure.
The lanthanum compound according to an embodiment may be
represented by Formula 1.
##STR00005##
In Formula 1, R.sup.1 may be, e.g., a hydrogen atom or a C1-C4
linear or branched alkyl group. R.sup.2 and R.sup.3 may each
independently be, e.g., a hydrogen atom or a C1-C5 linear or
branched alkyl group. In an implementation, at least one of R.sup.2
and R.sup.3 may be, e.g., a C3-C5 branched alkyl group. R.sup.4 may
be, e.g., a hydrogen atom or a C1-C4 linear or branched alkyl
group.
In an implementation, the lanthanum compound of Formula 1 may be an
asymmetrical amidinate, e.g., in which R.sup.2 and R.sup.3 are
substituents having different structures from each other (e.g., are
different substituents). For example, one of R.sup.2 and R.sup.3
may be a C3-C5 branched alkyl group, and the other one may be a
C1-C5 linear alkyl group. In an implementation, one of R.sup.2 and
R.sup.3 may be an iPr group, an iBu group, a tBu group, or an sBu
group, and the other one of R.sup.2 and R.sup.3 may be a Me group,
an Et group, an nPr group, or an nBu group. In an implementation,
R.sup.1 may be a hydrogen atom or a Me group, an Et group, an nPr
group, or an iPr group. R.sup.4 may be a Me group, an Et group, an
nPr group, or an iPr group.
In an implementation, the lanthanum compound of Formula 1 may have
a structure represented by one of Chemical Formulae 1 to 4.
##STR00006##
The lanthanum compound of Formula 1 (e.g., including an
asymmetrical amidinate in which R.sup.2 and R.sup.3 are
substituents having different structures) may be able to react at a
relatively low temperature. For example, a lanthanum-containing
film may be readily manufactured at a low temperature. In an
implementation, the lanthanum compound of Formula 1 (e.g.,
including an asymmetrical amidinate) may have excellent surface
adsorption properties. For example, the lanthanum compound may be
advantageously used in an atomic layer deposition (ALD)
process.
In synthesizing the lanthanum compound of Formula 1, when the
lanthanum compound including an asymmetrical amidinate (e.g., in
which R.sup.2 and R.sup.3 are substituents having different
structures) is synthesized, thermal stability of the lanthanum
compound may be increased in a process of synthesizing the
lanthanum compound, and also, an La precursor, which is in a liquid
state at room temperature (at atmospheric pressure), may be
obtained since a melting point of the lanthanum compound is
lowered.
In an implementation, one of the R.sup.2 and R.sup.3, which are
functional groups of the amidinate ligand, e.g., R.sup.2, may be a
bulky-type branched functional group having a three-dimensional
obstacle greater than the other one of R.sup.2 and R.sup.3, e.g.,
R.sup.3, and R.sup.3 may be a linear alkyl group. For example, the
polarity of the lanthanum compound of Formula 1 may be increased,
and as a result, an adsorption characteristic at a surface of a
substrate of the lanthanum compound may be increased. In this
manner, when the surface adsorption characteristic of the lanthanum
compound is increased, molecules of the lanthanum compound may show
a self-limiting growth behavior, and an ALD deposition
characteristic may be greatly increased. In an implementation, the
bulky-type branched functional group that constitutes one of the
functional groups, e.g., R.sup.2 and R.sup.3 of the amidinate
ligand, may help block attraction between adjacent molecules, and a
linear alkyl chain that constitutes the other one of R.sup.2 and
R.sup.3 may perform rotational and flexibility motions, and a
melting point of the lanthanum compound may be greatly reduced. For
example, the lanthanum compound may be in a liquid state at room
temperature.
In an implementation, the lanthanum compound (e.g., including an
asymmetrical amidinate in which R.sup.2 and R.sup.3 are
substituents having different structures) may readily react with
various reactive gases, e.g., O.sub.3 or NH.sub.3, at a relatively
lower temperature than other La precursors, the ALD characteristic
at a relatively low temperature may be increased.
In the lanthanum compound of Formula 1, a structure including the
asymmetrical amidinate (e.g., in which R.sup.2 and R.sup.3 are
substituents having different structures) may be formed as
follows.
First, a lanthanum tris[bis(trialkylsilyl)amide] complex may be
formed by reacting a lanthanum halide with a
bis(trialkylsilyl)amide alkali metal salt. The lanthanum halide may
be LaCl.sub.3.
Reaction Scheme 1 shows a process of forming the lanthanum
tris[bis(trialkylsilyl)amide] complex A-1.
##STR00007##
In Reaction Scheme 1, M indicates an alkali metal, and R.sup.X
indicates a C1-C2 alkyl group. In an implementation, M may be
sodium (Na), lithium (Li), or potassium (K).
As shown in Reaction Scheme 1, after reacting LaCl.sub.3 as a
lanthanum halide with bis(trialkylsilyl)amide alkali metal salt and
recrystallizing it, a lanthanum tris[bis(trialkylsilyl)amide]
complex A-1 may be formed.
As shown in Reaction Scheme 2 below, a Si-containing intermediate
A-2 may be formed by causing a reaction between the lanthanum
tris[bis(trialkylsilyl)amide] complex A-1 and
alkylcyclopentadiene.
##STR00008##
In Reaction Scheme 2, R.sup.1 may be defined the same as R.sup.1 of
Formula 1.
The Si-containing intermediate A-2 may be purified by
distillation.
As shown in Reaction Scheme 3, below, the lanthanum compound (e.g.,
including an asymmetrical amidinate) of Formula 1 may be formed by
causing a reaction between the Si-containing intermediate A-2 and a
bisalkylamidine compound.
##STR00009##
In Reaction Scheme 3, R.sup.1, R.sup.2, R.sup.3, and R.sup.4 may be
defined the same as those of Formula 1, and R.sup.2 and R.sup.3 may
be substituents having different structures from each other.
For example, in Reaction Scheme 3, N'-ethyl-N-isopropyl
acetimidamide of Chemical Formula 5 as the bisalkylamidine compound
may be used.
##STR00010##
An example method of manufacturing the N'-ethyl-N-isopropyl
acetimidamide in Chemical Formula 5 will be described in a
synthetic example (1) below.
As shown in Reaction Scheme 3, by reacting the Si-containing
intermediate A-2 with the bisalkylamidine compound and distilling a
resultant product, the lanthanum compound (PRODUCT) (e.g.,
including an asymmetrical amidinate) of Formula 1 may be
obtained.
In an implementation, in the lanthanum compound (PRODUCT) of
Formula 1, R.sup.2 and R.sup.3 may each independently be, e.g., a
C3-C5 branched alkyl group, and R.sup.4 may be, e.g., a C2-C4
linear or branched alkyl group. In an implementation, R.sup.2 and
R.sup.3 may each independently be, e.g., an iPr group, an iBu
group, a tBu group, or an sBu group. In an implementation, R.sup.2
and R.sup.3 may each independently be, e.g., branched alkyl groups
and may have the same structure. In an implementation, R.sup.1 may
be, e.g., a hydrogen atom, a Me group, an Et group, an nPr group,
or an iPr group. In an implementation, R.sup.4 may be a Me group,
an Et group, an nPr group, or an iPr group.
In an implementation, the lanthanum compound of Formula 1 may have
a structure represented by one of Chemical Formulae 6 to 10.
##STR00011##
In order to manufacture a compound having the structures of
Chemical Formulae 6 to 10, a method similar to the method described
with reference to Reaction Schemes 1 through 3 may be used. In an
implementation, in Reaction Scheme 3, diisopropyl acetamidine may
be used as the bisalkylamidine compound.
The lanthanum compound according to embodiments may be in a liquid
state at room temperature. For example, when the lanthanum compound
is used as a source in a process of manufacturing an integrated
circuit device, a central supply is possible in a manufacturing
facility. Therefore, it may not be necessary to stop the production
facility for changing the source. Accordingly, a loss due to
stopping the production facility may be reduced, and also, it is
possible to check a remaining amount of the lanthanum compound
source. Also, the lanthanum compound according to embodiments may
be appropriate for use as a lanthanum precursor when a film is
formed by using a deposition process, e.g., an ALD process or a
chemical vapor deposition (CVD) process including a vaporization
process. The lanthanum compound according to embodiments may have a
high reactivity with a reactive gas, e.g., O.sub.3, and may be
appropriate for use as a lanthanum precursor used particularly in
an ALD process.
The lanthanum compound according to embodiments may be vaporized by
using a bubbler or a vaporizer. For example, a process time of the
lanthanum compound may be reduced, a process reproducibility may be
high since there is no change in a deposition speed in a large
production system, and it may be advantageous for maintaining a
process distribution and for improving process defect.
The lanthanum compound according to embodiments may have excellent
ALD deposition characteristics, and a step-coverage of
approximately 95% or greater may be obtained in a complicated and
fine three-dimensional (3D) structure such as a Fin Field Effect
Transistor (FinFET) structure. A lanthanum containing film having
very low impurity content (e.g., of approximately 5% or less) may
be formed by using the lanthanum compound according to embodiments.
Accordingly, the lanthanum compound according to embodiments may be
very useful for forming a thin film in a next generation integrated
circuit.
The lanthanum compound according to embodiments may be used as a
source material of a lanthanum precursor composition for forming a
lanthanum containing film for configuring an integrated circuit or
for a manufacturing process of the integrated circuit.
FIG. 1 illustrates a flowchart of a method of forming a thin film,
according to embodiments.
Referring to FIG. 1, in operation P20, a substrate may be prepared.
The substrate may have the same configuration as a substrate 302
which will be described below with reference to FIG. 15.
In operation P30 of FIG. 1, a lanthanum-containing film may be
formed on the substrate by using a lanthanum compound that is a
liquid at room temperature.
The lanthanum compound may have the structure of Formula 1.
In an implementation, the lanthanum compound may include an
asymmetrical amidinate in which R.sup.2 and R.sup.3 are
substituents having different structures. For example, one of
R.sup.2 and R.sup.3 may be a C3-C5 branched alkyl group, and the
other one may be a C1-C5 linear alkyl group. For example, one of
R.sup.2 and R.sup.3 may be an iPr group, an iBu group, a tBu group,
or an sBu group, and the other one of R.sup.2 and R.sup.3 may be a
Me group, an Et group, an nPr group, or an nBu group. R.sup.1 may
be a Me group, an Et group, an nPr group, or an iPr group. R.sup.4
may be a Me group, an Et group, an nPr group, or an iPr group. For
example, the lanthanum compound may have a structure of one of
Chemical Formulae 1 through 4.
In an implementation, in the lanthanum compound, R.sup.2 and
R.sup.3 may each independently be, e.g., a C3-C5 branched alkyl
group, and R.sup.4 may be, e.g., a C2-C4 linear or branched alkyl
group. For example, R.sup.2 and R.sup.3 may each independently be
an iPr group, an iBu group, a tBu group, or an sBu group. For
example, R.sup.1 may be a hydrogen atom, a Me group, an Et group,
an nPr group, or an iPr group. R.sup.4 may be a Me group, an Et
group, an nPr group, or an iPr group. For example, the lanthanum
compound may have a structure represented by one of Chemical
Formulae 6 to 10.
In the method of forming a thin film according to an embodiment,
after forming a lanthanum containing film by using the lanthanum
compound of Formula 1, the method may further include an annealing
process under an inert atmosphere, an oxidation atmosphere, or a
reduction atmosphere. Also, in order to remove a step difference
formed on a surface of the lanthanum containing film, if desired, a
reflow process may be performed on the lanthanum containing film.
In an implementation, the annealing process and the reflow process
may be respectively performed at a temperature condition selected
in a range of about 250.degree. C. to about 1,000.degree. C., e.g.,
in a range of about 300.degree. C. to about 500.degree. C.
In the method of forming a thin film according to an embodiment, a
lanthanum containing film of a desired kind, e.g., a metal, oxide
ceramic, nitride ceramic, or glass, may be formed by appropriately
selecting the lanthanum compound of Formula 1, a different
precursor used together with the lanthanum compound of Formula 1, a
reactive gas, and a process condition for forming a thin film. In
an implementation, the lanthanum containing film formed according
to the method of forming a thin film may include, e.g., a
La.sub.2O.sub.3 film; a LaON film; a La--Ti compound oxide thin
film (LaTiO thin film); a La--Ti compound oxynitride thin film
(LaTiON thin film); a La--Al compound oxide thin film (LaAlO thin
film); a La--Al--Si compound oxide thin film; a La--Zr--Hf compound
oxide thin film; an La--Si--Zr--Hf compound oxide thin film; a
La--Ta--Nb compound oxide thin film; a La--Si--Ta--Nb compound
oxide thin film; a La-doped ferroelectric compound oxide thin film
(for example, a compound oxide thin film including La-doped lead
titanate, La-doped lead titanate zirconate, La-doped titanate
bismuth, or a material that further additionally includes Si in the
above compositions); a silica based glass thin film obtained from
at least one selected from a La-doped silicon oxide thin film, a
La-doped aluminum oxide, a La-doped germanium oxide, and a La-doped
titanium compound; a glass thin film including at least one
fluoride selected from a La-doped zirconium fluoride, La-doped
barium fluoride, La-doped aluminum fluoride, and La-doped sodium
fluoride; a La-doped tellurite glass thin film; a boron glass thin
film; a chalcogenide glass thin film; a sulfide glass thin film; a
bismuth glass thin film; a phosphate silicate glass thin film; a
boron silicate glass thin film; or a combination of these
materials.
In operation P30 of FIG. 1, in order to form a lanthanum containing
film, an ALD process or a CVD process may be used.
FIG. 2 illustrates a flowchart of a method of forming a lanthanum
oxide film according to embodiments by using an ALD process when
the lanthanum oxide film as the lanthanum containing film is formed
according to operation P30 of FIG. 1.
Referring to FIG. 2, in operation P40, the lanthanum compound may
be vaporized. The lanthanum compound may have a structure of
Formula 1.
In an implementation, the lanthanum compound may include an
asymmetrical amidinate in which R.sup.2 and R.sup.3 are
substituents having different structures. For example, one of
R.sup.2 and R.sup.3 is a C3-C5 branched alkyl group and the other
one of the R.sup.2 and R.sup.3 is a C1-C5 linear alkyl group. For
example, one of the R.sup.2 and R.sup.3 may be an iPr group, an iBu
group, a tBu group, or an sBu group, and the other one of the
R.sup.2 and R.sup.3 may be a Me group, an Et group, an nPr group,
or an nBu group. In an implementation, R.sup.1 may be a hydrogen
atom or a Me group, an Et group, an nPr group, or an iPr group.
R.sup.4 may be a Me group, an Et group, an nPr group, or an iPr
group. In an implementation, the lanthanum compound may have a
structure of one of the structures of Chemical Formulae 1 to 4.
In an implementation, in the lanthanum compound, R.sup.2 and
R.sup.3 may each independently be C3-C5 branched alkyl groups, and
R.sup.4 may be a C2-C4 linear or branched alkyl group. In an
implementation, the R.sup.2 and R.sup.3 may each independently be
iPr groups, iBu groups, tBu groups, or sBu groups. In an
implementation, R.sup.1 may be a hydrogen atom, a Me group, an Et
group, an nPr group, or an iPr group. The R.sup.4 may be a Me
group, an Et group, an nPr group, or an iPr group. For example, the
lanthanum compound may have a structure of one of the structures of
Chemical Formulae 6 to 10.
In operation P42, a La source adsorption layer may be formed on the
substrate by supplying the lanthanum compound vaporized according
to operation P40.
The substrate may have a structure of a substrate 302 which will be
described below with reference to FIG. 15.
The La source adsorption layer including a chemisorbed layer and a
physisorbed layer may be formed on the substrate by supplying the
vaporized lanthanum compound onto the substrate.
While the La source adsorption layer is formed on the substrate
according to operation P42, heat may be applied to the substrate by
heating the substrate or heating a reaction chamber, e.g., a
reaction chamber 254 which will be described below with reference
to FIGS. 3 through 6. The La source adsorption layer may have a
composition different from a lanthanum containing film which is a
target product. A process for forming the La source adsorption
layer may be performed at a temperature in a range of about room
temperature to about 400.degree. C., e.g., in a range of about
150.degree. C. to about 375.degree. C.
In an implementation, a process of heating the substrate on which
the La source adsorption layer is formed or a process of heat
treating the reaction chamber in which the substrate is
accommodated may further be performed. The heat treatment may be
performed in a range of room temperature to about 500.degree. C.,
e.g., in a range of about 150.degree. C. to about 500.degree.
C.
In operation P44, unnecessary by-products on the substrate may be
removed.
In an implementation, the unnecessary by-products may be removed by
supplying a purge gas onto the substrate. The purge gas may be,
e.g., an inert gas, such as Ar gas, He gas, or Ne gas or N.sub.2
gas.
In an implementation, in order to remove the unnecessary
by-products, a pressure of an inside of a reaction chamber, in
which the substrate is loaded, e.g., the reaction chamber 254 which
will be described below with reference to FIGS. 3 through 6 may be
reduced. In order to reduce the pressure of the reaction chamber, a
pressure in a range of about 0.01 kPa to about 50 kPa, e.g., in a
range of about 0.1 kPa to about 5 kPa may be applied.
In operation P46, a lanthanum oxide film may be formed by supplying
a reactive gas onto the La source adsorption layer formed on the
substrate.
The reactive gas may include, e.g., O.sub.2, O.sub.3, plasma
O.sub.2, H.sub.2O, NO.sub.2, NO, CO.sub.2, H.sub.2O.sub.2 or a
combination of these gases.
In an implementation, heat may be applied to the substrate while a
reactive gas is supplied onto the La source adsorption layer. In
this case, in order to apply heat to the substrate, a temperature
atmosphere in a range of room temperature to about 400.degree. C.,
e.g., in a range of about 150.degree. C. to about 375.degree. C.
may be maintained.
In operation P48, unnecessary by-products on the lanthanum oxide
film may be removed.
The process of removing the unnecessary by-products may be
performed as the same method described in operation P44.
In the method of forming a thin film according to an embodiment, a
series of operations from P40 to P48 illustrated in FIG. 2 may be
considered as one-cycle, and the cycle may be repeated a plurality
of times until the lanthanum oxide film having a desired thickness
is obtained.
In forming of the lanthanum oxide film according to the method of
forming a thin film, plasma energy, light, or a voltage may further
be applied. There is no specific time limitation in applying the
energy. For example, an energy applying process may further be
included when at least one of operation P42, operation P44,
operation P46, and operation P48 is performed or between each of
operations P42, P44, P46, and P48.
After forming the lanthanum oxide film according to the method of
forming a thin film, in order to obtain a further favorable
electrical characteristic, a process of annealing the lanthanum
oxide film under an inert gas atmosphere, an oxidizing atmosphere,
or a reducing atmosphere may further be performed. In an
implementation, to remove a step difference formed on a surface of
the lanthanum oxide film, a reflow process may be performed on the
lanthanum oxide film as desired. In an implementation, each of the
annealing and the reflow process may be performed under a
temperature condition selected in a range of about 250.degree. C.
to about 1,000.degree. C., e.g., about 300.degree. C. to about
500.degree. C.
For example, in order to form the lanthanum oxide film on the
substrate, the lanthanum compound of Formula 1 may be supplied onto
the substrate together with or sequentially at least one of a
different precursor, a reactive gas, a carrier gas, and a purge
gas. Details of the different precursor, the reactive gas, the
carrier gas, and the purge gas that may be supplied together with
the lanthanum compound of Formula 1 are described below.
The lanthanum compound according to an embodiment may be used in a
process of forming a thin film for manufacturing an integrated
circuit device. For example, the lanthanum compound may be used as
a La precursor in a process of forming a lanthanum containing film
by using an ALD process or a CVD process.
FIGS. 3 through 6 respectively show schematic configurations of
deposition devices 200A, 200B, 200C, and 200D as examples that may
be used in a process of forming a thin film according to
embodiments.
The deposition devices 200A, 200B, 200C, and 200D shown in FIGS. 3
to 6 respectively may include a fluid transmission unit 210, a
thin-film formation unit 250 configured to perform a deposition
process of forming a thin film on a substrate W using a process gas
supplied from a source container 212 included in the fluid
transmission unit 210, and an exhaust system 270 configured to
exhaust gases or by-products, which may remain in the thin-film
formation unit 250 after causing a reaction.
The thin-film formation unit 250 may include a reaction chamber 254
including a susceptor 252 configured to support the substrate W. A
shower head 256 may be installed at a top end unit of the inside of
the reaction chamber 254. The shower head 256 may be configured to
supply a gas supplied from the fluid transmission unit 210 onto the
substrate W.
The fluid transmission unit 210 may include an inlet line 222
configured to supply a carrier gas to the source container 212 from
the outside and an outlet line 224 configured to supply a source
compound contained in the source container 212 to the thin-film
formation unit 250. A valve V1 and a mass flow controller (MFC) M1
may be installed at the inlet line 222, and a valve V2 and an MFC
M2 may be installed at the outlet line 224. The inlet line 222 and
the outlet line 224 may be connected to each other through a bypass
line 226. A valve V3 may be installed at the bypass line 226. The
valve V3 may operate due to a pneumatic pressure by using an
electric motor or another remote control method.
The source compound supplied from the source container 212 may be
supplied into the reaction chamber 254 through an inlet line 266 of
the thin-film formation unit 250, which is connected to the outlet
line 224 of the fluid transmission unit 210. If necessary, the
source compound supplied from the source container 212 may be
supplied into the reaction chamber 254 together with a carrier gas
supplied through an inlet line 268. A valve V4 and an MFC M3 may be
installed at the inlet line 268 through which the carrier gas is
supplied.
The thin-film formation unit 250 may include an inlet line 262
configured to supply a purge gas into the reaction chamber 254 and
an inlet line 264 configured to supply a reactive gas. A valve V5
and an MFC M4 may be installed at the inlet line 262, and a valve
V6 and an MFC M5 may be installed at the inlet line 264.
The process gas used in the reaction chamber 254 and reaction
by-products to be discarded may be exhausted to the outside through
the exhaust system 270. The exhaust system 270 may include an
exhaust line 272 connected to the reaction chamber 254 and a vacuum
pump 274 installed at the exhaust line 272. The vacuum pump 274 may
perform a function of eliminating the process gas and the reaction
by-products, which are exhausted from the reaction chamber 254.
A trap 276 may be installed in the exhaust line 272 at an upstream
side of the vacuum pump 274. The trap 276 may trap, for example,
reaction by-products generated by unreacted process gases in the
reaction chamber 254 to prevent the reaction by-products from
flowing into the vacuum pump 274 installed at a downstream
side.
In the method of forming a thin film according to an embodiment,
the lanthanum compound of Formula 1 may be used as a source
compound.
In an implementation, the lanthanum compound may include an
asymmetrical amidinate in which R.sup.2 and R.sup.3 are
substituents having different structures. For example, one of the
R.sup.2 and R.sup.3 may be a C3-C5 branched alkyl group, and the
other one of the R.sup.2 and R.sup.3 may be a C1-C5 linear alkyl
group. For example, one of the R.sup.2 and R.sup.3 may be an iPr
group, an iBu group, a tBu group, or an sBu group, and the other
one of the R.sup.2 and R.sup.3 may be a Me group, an Et group, an
nPr group, or an nBu group. In an implementation, R.sup.1 may be a
hydrogen atom or a Me group, an Et group, an nPr group, or an iPr
group. R.sup.4 may be a Me group, an Et group, an nPr group, or an
iPr group. For example, the lanthanum compound may have a structure
represented by one of Chemical Formulae 1 through 4.
In an implementation, in the lanthanum compound, the R.sup.2 and
R.sup.3 may each independently be a C3-C5 branched alkyl group, and
R.sup.4 may be a C2-C4 linear or branched alkyl group. In an
implementation, the R.sup.2 and R.sup.3 may each independently be
an iPr group, an iBu group, a tBu group, or an sBu group. In an
implementation, the R.sup.1 may be a hydrogen atom or a Me group,
an Et group, an nPr group, or an iPr group. The R.sup.4 may be a Me
group, an Et group, an nPr group, or an iPr group. The lanthanum
compound may have a structure represented by one of Chemical
Formulae 6 to 10.
In an implementation, the lanthanum compound according to the
embodiment may be in a liquid state at room temperature, and may be
highly reactive with other process gases, e.g., a reactive gas,
such as a reducing gas. Accordingly, the trap 276 installed at the
exhaust line 272 may trap attachments, such as reaction by-products
which may be generated due to a reaction between the process gases
to prevent the attachments from flowing to a downstream side of the
trap 276. The trap 276 may have a configuration to be cooled by a
cooler or a water cooling device.
Also, a bypass line 278 and an automatic pressure controller (APC)
280 may be installed in the exhaust line 272 at an upstream side of
the trap 276. Valves V7 and V8 may be respectively installed in the
bypass line 278 and a portion of the exhaust line 272 extending
parallel to the bypass line 278.
As in the deposition devices 200A and 200C shown in FIGS. 3 and 5,
a heater 214 may be installed in the source container 212. A source
compound contained in the source container 212 may be maintained at
a relatively high temperature by the heater 214.
As in the deposition devices 200B and 200D shown in FIGS. 4 and 6,
a vaporizer 258 may be installed at the inlet line 266 of the
thin-film formation unit 250. The vaporizer 258 may vaporize a
fluid supplied in a liquid state from the fluid transmission unit
210 and may supply the vaporized source compound into the reaction
chamber 254. The source compound vaporized by the vaporizer 258 may
be supplied to the reaction chamber 254 together with a carrier gas
supplied through the inlet line 268. The supplying of the source
compound into the reaction chamber 254 through the vaporizer 258
may be controlled by a valve V9.
Also, as in the deposition devices 200C and 200D shown in FIGS. 5
and 6, in order to generate plasma in the reaction chamber 254, the
thin-film formation unit 250 may include a radio-frequency (RF)
power source 292 and an RF matching system 294, which are connected
to the reaction chamber 254.
In the deposition devices 200A, 200B, 200C, and 200D shown in FIGS.
3 to 6, one source container 212 is connected to the reaction
chamber 254 as examples. If desired, a plurality of source
containers 212 may be provided in the fluid transmission unit 210,
and each of the source containers 212 may be connected to the
reaction chamber 254.
In operation P40 of FIG. 2, the lanthanum compound may be vaporized
by using the vaporizer 258 of any one of the deposition devices
200B and 200D shown in FIGS. 4 and 6.
Also, in the method of forming the thin film according to the
embodiment, any one of the deposition devices 200A, 200B, 200C, and
200D shown in FIGS. 3 to 6 may be used to form the
lanthanum-containing film on the substrate W.
When performing the process of forming the lanthanum-containing
film described with reference to FIG. 1 or the process for forming
the lanthanum oxide film described with reference to FIG. 2, the
lanthanum compound of Formula 1 may be transported by using various
methods and supplied into a reaction chamber of a thin film forming
device, e.g., the reaction chamber 254 of each of the deposition
devices 200A, 200B, 200C, and 200D shown in FIGS. 3 to 6.
In an implementation, to form a thin film on the substrate W via a
CVD process by using the lanthanum compound of Formula 1, a gas
transporting method may be used. The gas transporting method may
include vaporizing the lanthanum compound of Formula 1 in the
source container 212 by applying heat and/or reducing pressure, and
supplying the vaporized lanthanum compound together with a carrier
gas (e.g., Ar, N.sub.2, and He) into the reaction chamber 254 as
desired.
In an implementation, in order to form a thin film via a CVD
process by using the lanthanum compound of Formula 1, a liquid
transporting method may be used. The liquid transporting method may
include transporting the lanthanum compound in a liquid state or a
solution state to the vaporizer 258, vaporizing the lanthanum
compound of Formula 1 in the vaporizer 258 by applying heat and/or
reducing a pressure, and supplying the vaporized lanthanum compound
into the reaction chamber 254. When the liquid transporting method
is used, the lanthanum compound according to the embodiment itself
or a solution in which the lanthanum compound is dissolved in an
organic solvent may be used as a source compound for forming a thin
film in the CVD process.
In an implementation, a multi-component CVD process may be used to
form a lanthanum-containing film in the method of forming the thin
film according to the embodiment. The multi-component CVD process
may be performed by using a method (hereinafter, referred to as a
"single source method") of independently vaporizing and supplying
respective components of a source compound to be used in a CVD
process or a method (hereinafter, referred to as a "cocktail source
method") of vaporizing and supplying a mixed source obtained by
previously mixing multi-component sources in a desired composition.
When the cocktail source method is used, a first mixture containing
the lanthanum compound of Formula 1, a first mixed solution in
which the first mixture is dissolved in an organic solvent, a
second mixture containing the lanthanum compound of Formula 1 and
other precursor, or a second mixed solution in which the second
mixture is dissolved in an organic solvent may be used as a source
compound for forming a thin film in a CVD process.
Suitable organic solvents may be used to obtain the first mixed
solution or the second mixed solution. For example, the organic
solvent may be acetate esters, such as ethyl acetate, n-butyl
acetate, and methoxyethyl acetate; ethers, such as tetrahydrofuran,
tetrahydropyran, ethylene glycol dimethyl ether, diethylene glycol
dimethyl ether, triethylene glycol dimethyl ether, dibutyl ether,
and dioxane; ketones, such as methyl butyl ketone, methyl isobutyl
ketone, ethyl butyl ketone, dipropyl ketone, diisobutyl ketone,
methyl amyl ketone, cyclohexanone, and methylcyclohexanone;
hydrocarbons, such as hexane, cylclohexane, methylcyclohexane,
dimethylcyclohexane, ethylcyclohexane, heptane, octane, toluene,
and xylene; hydrocarbons having a cyano group, such as
1-cyanopropane, 1-cyanobutane, 1-cyanohexane, cyanocyclohexane,
cyanobenzene, 1,3-dicyanopropane, 1,4-dicyanobutane,
1,6-dicyanohexane, 1,4-dicyanocyclohexane, and 1,4-dicyanobenzene;
pyridine; or lutidine. The organic solvents describe above may be
used alone or in a mixture of at least two kinds of these materials
depending on solubilities, process temperatures, boiling points,
and ignition points of solutes. When the organic solvent is used,
the total amount of the lanthanum compound of Formula 1 and other
precursor may range from about 0.01 mol/L to about 2.0 mol/L, for
example, about 0.05 mol/L to about 1.0 mol/L in the organic
solvent.
In the method of forming the thin film according to the embodiment,
when the multi-component CVD process is used to form the
lanthanum-containing film, other suitable precursors may be used
together with the lanthanum compound according to the
embodiment.
In an implementation, other precursor that may be used in the
method of forming a thin film according to the embodiment may
include an organic coordination compound of at least one of an
alcohol compound, a glycol compound, a .beta.-diketone compound, a
cyclopentadiene compound, and an organic amine compound, and any
one selected from silicon and a metal. In an implementation, the
metal may include, e.g., magnesium (Mg), calcium (Ca), strontium
(Sr), barium (Ba), titanium (Ti), zirconium (Zr), hafnium (Hf),
vanadium (V), niobium (Nb), tantalum (Ta), manganese (Mn),
palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au),
zinc (Zn), aluminum (Al), gallium (Ga), indium (In), germanium
(Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi), yttrium
(Y), nickel (Ni), cerium (Ce), praseodymium (Pr), neodymium (Nd),
promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd),
terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium
(Tm), or ytterbium (Yb).
The alcohol compound that may be used as the organic ligand
compound of the other precursor may be, e.g., alkyl-alcohols, such
as methanol, ethanol, propanol, isopropyl alcohol, butanol,
sec-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, pentyl
alcohol, isopentyl alcohol, and 3-pentyl alcohol; ether-alcohols,
such as 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol,
2-(2-methoxyethoxy)ethanol, 2-methoxy-1-methylethanol,
2-methoxy-1,1-dimethylethanol, 2-ethoxy-1,1-dimethylethanol,
2-propoxy-1,1-diethylethanol, 2-butoxy-1,1-diethylethanol,
2-(2-methoxyethoxy)-1,1-dimethylethanol,
2-propoxy-1,1-diethylethanol, 2-s-butoxy-1,1-diethylethanol, and
3-methoxy-1,1-dimethylpropanol; and dialkyl amino alcohol.
The glycol compound that may be used as the organic ligand compound
of the other precursor may be, e.g., 1,2-ethanediol,
1,2-propanediol, 1,3-propanediol, 2,4-hexanediol,
2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol,
1,3-butanediol, 2,4-butanediol, 2,2-diethyl-1,3-butanediol,
2-ethyl-2-butyl-1,3-propanediol, 2,4-pentanediol,
2-methyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 2,4-hexanediol,
and 2,4-dimethyl-2,4-pentanediol.
The .beta.-diketone compound that may be used as the organic ligand
compound of the other precursor may be, e.g., alkyl-substituted
(.beta.-diketones, such as acetylacetone, hexane-2,4-dione,
5-methylhexane-2,4-dione, heptane-2,4-dione,
2-methylheptane-3,5-dione, 5-methylheptane-2,4-dione,
6-methylheptane-2,4-dione, 2,2-dimethylheptane-3,5-dione,
2,6-dimethylheptane-3,5-dione, 2,2,6-trimethylheptane-3,5-dione,
2,2,6,6-tetramethylheptane-3,5-dione, octane-2,4-dione,
2,2,6-trimethyloctane-3,5-dione, 2,6-dimethyloctane-3,5-dione,
2,9-dimethylnonane-4,6-dione, 2-methyl-6-ethyldecane-3,5-dione, and
2,2-dimethyl-6-ethyldecane-3,5-dione; fluorine-substituted alkyl
.beta.-diketones, such as 1,1,1-trifluoropentane-2,4-dione,
1,1,1-trifluoro-5,5-dimethylhexane-2,4-dione,
1,1,1,5,5,5-hexafluoropentane-2,4-dione, and
1,3-diperfluorohexylpropane-1,3-dione; and ether-substituted
.beta.-diketones, such as
1,1,5,5-tetramethyl-1-methoxyhexane-2,4-dione,
2,2,6,6-tetramethyl-1-methoxyheptane-3,5-dione, and
2,2,6,6-tetramethyl-1-(2-methoxyethoxy)heptane-3,5-dione.
The cyclopentadiene compound that may be used as the organic ligand
compound of the other precursor may be, e.g., cyclopentadiene,
methylcyclopentadiene, ethylcyclopentadiene, propylcyclopentadiene,
isopropylcyclopentadiene, butylcyclopentadiene,
sec-butylcyclopentadiene, isobutylcyclopentadiene,
tert-butylcyclepentadiene, dimethylcyclopentadiene, or
tetramethylcyclopentadiene.
The organic amine compound that may be used as the organic ligand
compound of the other precursor may be, e.g., methylamine,
ethylamine, propylamine, isopropylamine, dimethylamine,
diethylamine, dipropylamine, diisopropylamine, ethylmethylamine,
propylmethylamine, or isopropylmethylamine.
In the method of forming a thin film according to the embodiment, a
vapor obtained by vaporizing the lanthanum compound of Formula 1 or
a mixture of the lanthanum compound of Formula 1 and other
precursor may be supplied onto a substrate together with a reactive
gas that is used as needed. Thus, a lanthanum-containing film may
be grown and deposited on the substrate by continuously decomposing
and/or reacting precursors on the substrate in accordance with a
CVD process.
In the method of forming a thin film according to the embodiment, a
suitable method of transporting a source compound, a suitable
deposition method, suitable synthesis conditions, and suitable
synthesis equipment may be used.
The reactive gas that may be used in a method of forming a thin
film according to the embodiment may include an oxidizing gas, a
reducing gas, or a nitrogen-containing gas.
The oxidizing gas may include, e.g., oxygen, ozone, nitrogen
dioxide, nitrogen monoxide, water vapor, hydrogen peroxide, a
formic acid, a nitric acid, or an acetic acid.
The reducing gas may include, e.g., hydrogen, ammonia, or an
organic metal compound.
The nitrogen-containing gas may include, e.g., an organic amine
compound, such as monoalkylamine, dialkylamine, trialkylamine, and
alkylenediamine, hydrazine, or ammonia.
In the method of forming the thin film according to the embodiment,
a vapor transporting method, a liquid transporting method, a single
source method, or a cocktail source method may be used to supply
the source compound to the reaction chamber 254.
In the method of forming the thin film according to the embodiment,
one of the following processes may be used to form the
lanthanum-containing film. For example, the process includes: a
thermal CVD process in which a thin film is formed by reacting the
vaporized source compound or both the vaporized source compound and
a reactive gas by heat; a plasma CVD process in which a thin film
is formed by using heat and plasma; a photo-CVD process in which a
thin film is formed by using heat and light; a photo-plasma CVD
process in which a thin film is formed by using heat, light, and
plasma, or an ALD process in which a thin film is deposited by
stages on a molecular level.
In the method of forming the thin film according to the embodiment,
thin film forming conditions for forming the lanthanum-containing
film may include a reaction temperature (or substrate temperature),
a reaction pressure, and a deposition speed.
The reaction temperature may be a temperature at which the
lanthanum compound of Formula 1 may sufficiently react. In an
implementation, the reaction temperature may be, e.g., a
temperature of about 100.degree. C. or higher. In an
implementation, the reaction temperature may be, e.g., selected in
the range of about 150.degree. C. to about 500.degree. C.
In an implementation, the reaction pressure may be selected in a
range of an atmospheric pressure to about 10 Pa in a thermal CVD
process or a photo-CVD process and may be selected in a range of
about 10 Pa to about 2000 Pa in a plasma process.
Also, a deposition speed may be controlled by controlling supply
conditions (e.g., a vaporization temperature and a vaporization
pressure) of a source compound, a reaction temperature, and a
reaction pressure. In the method of forming the thin film according
to the embodiment, a deposition speed of the lanthanum-containing
film may be selected in the range of about 0.01 nm/min to about
5000 nm/min, e.g., in a range of about 0.1 nm/min to about 1000
nm/min.
When the lanthanum-containing film is formed by using an ALD
process, the number of cycles of ALD processes may be adjusted to
control a thickness of the lanthanum-containing film.
When the lanthanum oxide film is formed by using the ALD process,
energy (e.g., plasma, light, or a voltage) may be applied. Time
points at which the energy is applied may be variously selected.
For example, the energy (e.g., plasma, light, or a voltage) may be
applied: at a time point when a source gas containing the lanthanum
compound is introduced into the reaction chamber 254; a time point
when the source gas is adsorbed on the substrate; at a time when an
exhaust process is performed by using a purge gas; a time point
when a reactive gas is introduced into the reaction chamber 254; or
between the respective time points.
A lanthanum-containing film formed by using the method of forming
the thin film according to the embodiment may be used for various
purposes. For example, the lanthanum-containing film may be used
for a gate dielectric film of a transistor, a conductive barrier
film used for interconnections, a resistive film, a magnetic film,
a barrier metal film for liquid crystals, a member for thin film
solar cells, a member for semiconductor equipment, a nanostructure,
a hydrogen storage alloy, a microelectromechanical systems (MEMS)
device, or an actuator.
Hereinafter, synthesis examples and estimation examples of the
lanthanum compound according to the embodiment will be
described.
The following Examples and Comparative Examples are provided in
order to highlight characteristics of one or more embodiments, but
it will be understood that the Examples and Comparative Examples
are not to be construed as limiting the scope of the embodiments,
nor are the Comparative Examples to be construed as being outside
the scope of the embodiments. Further, it will be understood that
the embodiments are not limited to the particular details described
in the Examples and Comparative Examples.
Synthesis Example 1
Synthesis of an Intermediate Compound (N'-ethyl-N-isopropyl
acetimidamide) Expressed as Chemical Formula 5
A synthesis process of the intermediate compound expressed as
Chemical Formula 5 is schematically shown in Reaction Scheme 4.
##STR00012##
22 g of isopropylisocyanate and 180 g of dehydrated tetrahydrofuran
were placed in a reaction flask and cooled under an argon (Ar)
atmosphere. Next, 130 g (1 molar equivalent) of
ethylamine-tetrahydrofuran solution was slowly dropped into the
reaction flask, and the mixture was kept for 4 hours at room
temperature to cause a reaction. Then, a solvent was removed, 500 g
of dehydrated dichloromethane and 50 g of triethylamine were put
into the reaction flask, and the resultant product was cooled.
Then, 100 g of p-toluenesulfonyl chloride dissolved in 500 g
dehydrated dichloromethane was slowly dropped into the reaction
flask and stirred for 10 hours at room temperature. The obtained
solution was neutralized with a potassium carbonate aqueous
solution. Then, a divided oil layer was removed and dried with a
dehydrating agent. Next, after removing a solvent, a liquid phase
was extracted with diethylene ether, and N'-ethyl-N-isopropyl
carbodiimide was distilled and separated by removing the solvent
again. After adding 20 g of diethylene ether to the resultant and
cooling the resultant product, 60 g of a methyllithium diethyl
ether solution corresponding to 1 molar equivalent of carbodiimide
included in the resultant product was slowly dropped to the
resultant product and kept for 5 hours at room temperature to cause
a reaction. 50 g of deionized water was slowly dropped to the
resultant product and an oil layer was separated. The oil layer was
dried with a dehydrating agent and desolventized. Then, 3.4 g of a
target material was obtained by distilling and purifying the
desolventized product under a reduced pressure of about 40 Pa at a
temperature of about 30.degree. C. to about 50.degree. C.
[Analysis]
.sup.1H-NMR (solvent: hexadeuterobenzene) (Chemical shift:
multiplicity: number of hydrogens)
(1.138:s:6H), (1.150:s:3H), (1.325:s:3H), (2.735:s:1H),
(3.249:m:2H), (3.856:s:1H)
Synthesis Example 2
Synthesis of the Lanthanum Compound of Chemical Formula 1
20 g of lanthanum tris(bis-trimethylsilylamide) complex and 60 g of
dehydrated toluene were placed in a reaction flask under an Ar
atmosphere, and 6.1 g (2 molar equivalents) of ethylcyclopentadiene
was slowly dropped at room temperature into the reaction flask.
Thereafter, the mixture was heated at a temperature of about
40.degree. C. for about 5 hours and then heated at a temperature of
about 60.degree. C. for about 3 hours to cause a reaction. After
desolventizing the resultant product, the desolventized resultant
product was distilled and purified by heating the desolventized
resultant product to a temperature of about 140.degree. C. under a
reduced pressure of about 40 Pa. 10 g of dehydrated toluene was
added to the reaction flask, and 4.7 g of N-(tert-butyl)-N'-ethyl
acetimidamide was slowly dropped into the reaction flask at room
temperature. The resultant product was heated at a temperature of
about 50.degree. C. for about 3 hours and desolventized. Then, 6.8
g of a target material was obtained by distilling and purifying the
desolventized resultant product under a reduced pressure of about
40 Pa and by separating a fraction at a temperature of about
135.degree. C. to about 175.degree. C.
[Analysis]
(1) Element analysis (analysis of metals: inductively coupled
plasma-atomic emission spectroscopy (ICP-AES))
La: 30.1% (theoretical value: 29.78%), C: 56.5% (theoretical value:
56.65%), H: 7.7% (theoretical value: 7.56%), N: 5.7% (theoretical
value: 6.01%)
(2) .sup.1H-NMR (solvent: hexadeuterobenzene) (Chemical shift:
multiplicity: number of hydrogens)
(1.052:t:3H), (1.089:s:9H), (1.232:t:6H), (1.578:s:3H),
(2.576:m:4H), (2.895:m:2H), (6.099:d:8H)
(3) TG-DTA (thermogravimetric differential thermal analysis)
TGA (Ar 100 ml/min, heating rate of about 10.degree. C./min, sample
amount of about 9.718 mg)
50 mass % reduced temperature of about 266.8.degree. C.
Synthesis Example 3
Synthesis of the Lanthanum Compound of Chemical Formula 2
20 g of lanthanum tris(bis-trimethylsilylamide) complex and 60 g of
dehydrated toluene were placed in a reaction flask under an Ar
atmosphere, and 6.1 g (2 molar equivalents) of ethyl
cyclopentadiene was slowly dropped at room temperature into the
reaction flask. Thereafter, the mixture was heated at a temperature
of about 40.degree. C. for about 5 hours and then heated at a
temperature of about 60.degree. C. for about 3 hours to cause a
reaction. After desolventizing the resultant product, the
desolventized resultant product was distilled and purified by
heating to a temperature of about 140.degree. C. under a reduced
pressure of about 40 Pa. 20 g of dehydrated toluene was added to
the reaction flask, and 4.2 g of N'-ethyl-N-isopropyl acetimidamide
was slowly dropped into the reaction flask at room temperature. The
resultant product was heated at a temperature of about 50.degree.
C. for about 3 hours and desolventized. Then, 7.1 g of a target
material was obtained by distilling and purifying the desolventized
product under a reduced pressure of about 40 Pa and by separating a
fraction at a temperature of about 120.degree. C. to about
170.degree. C.
[Analysis]
(1) Element analysis (ICP-AES)
La: 30.9% (theoretical value: 30.70%), C: 55.4% (theoretical value:
55.75%), H: 7.7% (theoretical value: 7.35%), N: 6.0% (theoretical
value: 6.19%)
(2) .sup.1H-NMR (solvent: hexadeuterobenzene) (Chemical shift:
multiplicity: number of hydrogens)
(0.965:d:6H), (1.039:t:3H), (1.220:t:6H), (1.478:s:3H),
(2.561:m:4H), (2.936:m:2H), (3.279:t:1H). (6.099:d:8H)
(3) TG-DTA
TGA (Ar 100 ml/min. heating rate of about 10.degree. C./min, sample
amount of about 9.002 mg)
50 mass % reduced temperature of about 257.9.degree. C.
Synthesis Example 4
Synthesis of the Lanthanum Compound of Chemical Formula 3
20 g of lanthanum tris(bis-trimethylsilylamide) complex and 60 g of
dehydrated toluene were placed in a reaction flask under an Ar
atmosphere, and 7.0 g (2 molar equivalents) of normal propyl
cyclopentadiene was slowly dropped at room temperature into the
reaction flask. Then, the mixture was heated at a temperature of
about 40.degree. C. for about 5 hours and then heated at a
temperature of about 60.degree. C. for about 5 hours to cause a
reaction. After desolventizing the resultant product, the
desolventized resultant product was distilled and purified by
heating to a temperature of about 145.degree. C. under a reduced
pressure of about 40 Pa. 20 g of dehydrated toluene was added to
the reaction flask, and 4.2 g of N'-ethyl-N-isopropyl acetimidamide
was slowly dropped into the reaction flask at room temperature. The
resultant product was heated at a temperature of about 50.degree.
C. for about 3 hours and desolventized. Then, 7.5 g of a target
material was obtained by distilling and purifying the desolventized
product under a reduced pressure of about 40 Pa and by separating a
fraction at a temperature of about 130.degree. C. to about
180.degree. C.
[Analysis]
(1) Analysis of elements (analysis of metals: ICP-AES)
La: 29.1% (theoretical value: 28.91%), C: 57.3% (theoretical value:
57.5%), H: 7.8% (theoretical value: 7.76%), N: 5.8% (theoretical
value: 5.83%)
(2) .sup.1H-NMR (solvent: hexadeuterobenzene) (Chemical shift:
multiplicity: number of hydrogens)
(0.941:d:6H), (0.966:t:6H), (1.053:t:3H), (1.494:s:3H),
(1.622:m:4H), (2.522:t:4H). (2.946:m:2H), (3.299:t:1H),
(6.097:t:4H), (6.183:s:4H)
(3) TG-DTA
TG-DTA (Ar 100 ml/min, heating rate of about 10.degree. C./min,
sample amount of about 9.745 mg)
50 mass % reduced temperature of about 267.3.degree. C.
FIG. 7 illustrates a graph of a TG-DTA analysis result of a
lanthanum compound of Chemical Formula 3 obtained in Synthesis
Example 4.
FIG. 8 illustrates a graph of a differential scanning calorimetry
(DSC) analysis result of the lanthanum compound of Chemical Formula
3 obtained in Synthesis Example 4.
Synthesis Example 5
Synthesis of the Lanthanum Compound of Chemical Formula 4
20 g of lanthanum tris(bis-trimethylsilylamide) complex and 60 g of
dehydrated toluene were placed in a reaction flask under an Ar
atmosphere, and 7.0 g (2 molar equivalents) of isopropyl
cyclopentadiene was slowly dropped at room temperature into the
reaction flask. Then, the mixture was heated at a temperature of
about 40.degree. C. for about 5 hours and then heated at a
temperature of about 60.degree. C. for about 5 hours to cause a
reaction. The resultant product was desolventized, and the
desolventized resultant product was then distilled and purified by
heating the desolventized resultant product to a temperature of
about 145.degree. C. under a reduced pressure of about 40 Pa. 20 g
of dehydrated toluene was added in the reaction flask, and 4.2 g of
N'-ethyl-N-isopropyl acetimidamide was slowly dropped into the
reaction flask at room temperature. The resultant product was
heated at a temperature of about 50.degree. C. for about 3 hours
and desolventized. Then, 7.9 g of a target material was obtained by
distilling and purifying the desolventized product under a reduced
pressure of about 40 Pa and by separating a fraction at a
temperature of about 130.degree. C. to about 180.degree. C.
[Analysis]
(1) Analysis of elements (analysis of metals: ICP-AES)
La: 28.5% (theoretical value: 28.91%), C: 56.3% (theoretical value:
57.5%), H: 8.2% (theoretical value: 7.76%), N: 7.0% (theoretical
value: 5.83%)
(2) .sup.1H-NMR (solvent: hexadeuterobenzene) (Chemical shift:
multiplicity: number of hydrogens)
(0.989:d:6H), (1.054:t:3H), (1.238:d:12H), (1.490:s:3H),
(2.876:m:2H), (2.952:m:2H), (3.297:t:1H), (6.174:d:8H)
(3) TG-DTA
TG-DTA (Ar 100 ml/min, heating rate of about 10.degree. C./min,
sample amount of about 9.522 mg)
50 mass % reduced temperature of about 270.4.degree. C.
FIG. 9 illustrates a graph of a TG-DTA analysis result of a
lanthanum compound of Chemical Formula 4 obtained in Synthesis
Example 5.
FIG. 10 illustrates a graph of a DSC analysis result of the
lanthanum compound of Chemical Formula 4 obtained in Synthesis
example 5.
Synthesis Example 6
Synthesis of the Lanthanum Compound of Chemical Formula 8
40 g of lanthanum tris(bis-trimethylsilylamide) complex and 120 g
of dehydrated toluene were placed in a reaction flask under an Ar
atmosphere, and 12.1 g (2 molar equivalents) of ethyl
cyclopentadiene was slowly dropped into the reaction flask at room
temperature. Then, the mixture was heated at a temperature of about
40.degree. C. for about 5 hours and then heated at a temperature of
about 60.degree. C. for about 3 hours to cause a reaction. The
resultant product was desolventized, and the desolventized
resultant product was then distilled and purified by heating the
desolventized resultant product to a temperature of about
140.degree. C. under a reduced pressure of about 40 Pa. 20 g of
dehydrated toluene was added to the reaction flask, and 10.1 g of
diisopropyl propionimidamide was slowly dropped into the reaction
flask at room temperature. The resultant product was heated at a
temperature of about 50.degree. C. for about 3 hours and
desolventized. Then, 13.0 g of a target material was obtained by
distilling and purifying the desolventized product under a reduced
pressure of about 40 Pa and by separating a fraction at a
temperature of about 135.degree. C. to about 170.degree. C.
[Analysis]
(1) Analysis of elements (analysis of metals: ICP-AES)
La: 29.1% (theoretical value: 28.91%), C: 58.0% (theoretical value:
57.50%), H: 7.2% (theoretical value: 7.76%), N: 5.7% (theoretical
value: 5.83%)
(2) .sup.1H-NMR (solvent: hexadeuterobenzene) (Chemical shift:
multiplicity: number of hydrogens)
(0.909:t:3H), (0.987:d:12H), (1.240:t:6H), (1.951:m:2H),
(2.588:m:4H), (3.335:m:2H), (6.117:d:8H)
(3) TG-DTA
TG-DTA (Ar 100 ml/min, heating rate of about 10.degree. C./min,
sample amount of about 10.754 mg)
50 mass % reduced temperature of about 268.5.degree. C.
FIG. 11 illustrates a graph of a TG-DTA analysis result of the
lanthanum compound of Chemical Formula 8 obtained in Synthesis
Example 6.
FIG. 12 illustrates a graph of a DSC analysis result of the
lanthanum compound of Chemical Formula 8 obtained in Synthesis
Example 6.
Estimation Example 1
Formation Example 1 of a Lanthanum Oxide Film
A lanthanum oxide film was formed on a silicon substrate via an ALD
process using the lanthanum compound of Chemical Formula 8 obtained
in Synthesis Example 6 as a material using the deposition device
200A shown in FIG. 3.
In the present Estimation Example 1, the ALD process was performed
at a reaction temperature (substrate temperature) of about
150.degree. C. to about 350.degree. C. by using a gas mixture, in
which O.sub.3 and O.sub.2 are mixed in a mass ratio of 20 wt %:80
wt %, as a reactive gas.
For the present estimation, a single cycle including a series of
processes (1) to (4) described below was repeated 100 times.
(1) a process of introducing the vaporized lanthanum compound of
Chemical Formula 8 into a reaction chamber and adsorbing the
vaporized lanthanum compound of Chemical Formula 8 onto a substrate
for about 10 seconds under a pressure of about 93 Pa
(2) a process of performing a purge process using argon for about
10 seconds and removing unreacted sources from the reaction
chamber
(3) a process of introducing a reactive gas into the reaction
chamber and causing a reaction for about 10 seconds under a
pressure of about 93 Pa
(4) a process of performing a purge process using argon for about
10 seconds and removing unreacted sources from the reaction
chamber
From a thickness measuring result of thin films by X-ray
reflectometry (XRR) and confirmation results of structure and
composition of the thin films by X-ray photoelectron spectroscopy
(XPS), all part of the thin film obtained in Estimation Example 1
was lanthanum oxide film, and a thickness in a range from about 1.0
.ANG. to about 1.5 .ANG. was obtained in each cycle of the ALD
process.
FIG. 13 illustrates a graph of a deposition rate relative to a
deposition temperature in a process of forming a lanthanum oxide
film in the Estimation Example 1 described above.
From the Estimation result of FIG. 13, it may be seen that a
temperature section in which the deposition speed is constant even
though the deposition temperature is increased, that is, the ALD
behavior section, is in a range of about 250.degree. C. to about
300.degree. C.
FIG. 14 illustrates a graph showing an Estimation result by an
X-ray fluorescence (XRF) to confirm a thickness variation relative
to a deposition cycle at a relatively low temperature condition in
which the temperature inside the reaction chamber is 175.degree.
C.
From the Estimation result of FIG. 14, it is confirmed that there
was no incubation time at the initial stage of the deposition under
a relatively low temperature condition in which the temperature
inside the reaction chamber was 175.degree. C.
Estimation Example 2
Formation Example 2 of a Lanthanum Oxide Film
A lanthanum oxide film was formed on a silicon substrate by using
the same method used in Estimation Example 1 except that the
lanthanum compound of Chemical Formula 10 was used as a material
instead of the lanthanum compound of Chemical Formula 8.
From a thickness measuring result of thin films by XRR and
confirmation results of structure and composition of the thin films
by XPS, all part of the thin film obtained in Estimation Example 2
was lanthanum oxide film, and a thickness in a range from about 0.5
.ANG. to about 0.6 .ANG. was obtained in each cycle of the ALD
process.
As it is seen from the Estimation Examples 1 and 2, in the
lanthanum compound of Formula 1 according to the embodiment, the
thickness of the lanthanum oxide film obtained in each cycle of the
ALD process is greater when the R.sup.4 is an ethyl group than a
methyl group, and accordingly, the productivity of the process of
forming the lanthanum oxide film is increased.
FIG. 15 illustrates a perspective view of an integrated circuit
device 300 according to an embodiment.
Referring to FIG. 15, the integrated circuit device 300 may include
a fin-type active region FA protruding from a substrate 302. The
fin-type active region FA may extend in a direction (in a Y
direction in FIG. 15).
The substrate 302 may include a semiconductor, such as Si or Ge, or
a compound semiconductor, such as SiGe, SiC, GaAs, InAs, or
InP.
A device isolation film 310 covering a lower sidewall of the
fin-type active region FA may be formed on the substrate 302. The
fin-type active region FA may protrude in a fin shape on the device
isolation film 310. In some embodiments, the device isolation film
310 may include a silicon oxide film, a silicon nitride film, a
silicon oxynitride film, or a combination thereof.
A gate structure 320 may be formed on the fin-type active region FA
formed on the substrate 302. The gate structure 320 may extend in a
direction (an X direction) crossing an extending direction of the
fin-type active region FA. A pair of source and drain regions 330
may be formed on both sides of the gate structure 320 on the
fin-type active region FA. The pair of source and drain regions 330
may include a semiconductor layer epitaxially grown from the
fin-type active region FA. Each of the pair of source and drain
regions 330 may include a plurality of epitaxially grown SiGe
layers, an epitaxially grown silicon layer, or an epitaxially grown
SiC layer.
A transistor TR may be formed on an intersection between the
fin-type active region FA and gate structure 320. The transistor TR
may have a three-dimensional structure in which channels are formed
on an upper surface and both side surfaces of the fin-type active
region FA. The transistor TR may constitute an NMOS transistor or a
PMOS transistor.
FIGS. 16A through 16G illustrate cross-sectional views of stages in
a method of manufacturing the integrated circuit device 300 of FIG.
15. In FIGS. 16A through 16G, (A) is a cross-sectional view of a
portion corresponding to a cross-section in the X direction of FIG.
15, and (B) is a cross-sectional view of a portion corresponding to
a cross-section in the Y direction of FIG. 15. In FIGS. 16A through
16G, like reference numerals are used to indicate elements that are
substantially identical to the elements of FIG. 15, and thus the
detailed description thereof may not be repeated.
Referring to FIG. 16A, the fin-type active region FA may be formed
by partially etching the substrate 302. The fin-type active region
FA may have a structure extending in the Y direction on the
substrate 302.
Referring to FIG. 16B, the device isolation film 310 covering both
lower sidewalls of the fin-type active region FA may be formed.
After forming the device isolation film 310, an upper part of the
fin-type active region FA may have a structure protruding above the
device isolation film 310.
Referring to FIG. 16C, a dummy gate structure DG including a dummy
gate insulating film 314D and a dummy gate electrode 320D may be
formed. The dummy gate structure DG may cover an upper portion of
the fin-type active region FA. Insulating spacers 342 covering both
sidewalls of the dummy gate structure DG may be formed. Afterwards,
source and drain regions 330 may be formed in the fin-type active
region FA on both sides of the dummy gate structure DG. An
interlayer insulating film 344 covering the source and drain
regions 330 may be formed on both sides of the dummy gate structure
DG.
The dummy gate structure DG may extend in a direction (an X
direction) crossing an extending direction of the fin-type active
region FA. In some embodiments, the dummy gate insulating film 314D
may include a silicon oxide film, the dummy gate electrode 320D may
include polysilicon, and the insulating spacers 342 may include a
silicon nitride film. The interlayer insulating film 344 may
include a silicon oxide film, a silicon nitride film, or a
combination of these materials.
Referring to FIG. 16D, the dummy gate structure DG exposed through
the interlayer insulating film 344 may be removed, and thus, the
fin-type active region FA is through a gate space GS between a pair
of insulating spacers 342.
Referring to FIG. 16E, an interface layer 312 and a high-k
dielectric film 314 may be sequentially formed on the surface of
the fin-type active region FA exposed through the gate space
GS.
The interface layer 312 may constitute a gate insulating film
together with the high-k dielectric film 314. The interface layer
312 may include an insulating material, such as an oxide film, a
nitride film, or an oxynitride film. The high-k dielectric film 314
may include a metal oxide or a metal oxynitride having a dielectric
constant in a range of about 10 to about 25. For example, the
high-k dielectric film 314 may include hafnium oxide, hafnium
oxynitride, hafnium silicon oxide, zirconium oxide, or zirconium
silicon oxide. The high-k dielectric film 314 may be formed by an
ALD process or a CVD process.
Afterwards, a lanthanum-containing film 324 is formed on the high-k
dielectric film 314 by using the lanthanum compound of Formula 1
according to the embodiment. In an implementation, the
lanthanum-containing film 324 may include a La.sub.2O.sub.3 thin
film. In order to form the lanthanum-containing film 324, the
method of forming a thin film described with reference to FIGS. 1
and 2 may be used.
Next, a first metal-containing layer 326A may be formed on the
lanthanum-containing film 324. The first metal-containing layer
326A may include TiN, TaN, TiAlN, TaAlN, TiSiN, or a combination of
these materials.
Referring to FIG. 16F, the resultant product in which the first
metal-containing layer 326A is exposed may be heat-treated HT1 in
the gate space GS. The heat-treatment HT1 may be performed, e.g.,
at a temperature in a range of about 400.degree. C. to about
600.degree. C. for about 5 minutes to about 1 hour. Due to the
heat-treatment HT1, La atoms may be diffused to an interface
between the interface layer 312 and the high-k dielectric film 314
from the lanthanum-containing film 324.
An amount of La atoms that diffuse into the interface between the
interface layer 312 and the high-k dielectric film 314 may be
controlled by using various methods based on the result of the heat
treatment HT1. For example, the amount of La atoms present in the
interface between the interface layer 312 and the high-k dielectric
film 314 may be controlled by using film quality and a film
thickness of the high-k dielectric film 314 and a temperature of
the heat-treatment HT1. In an implementation, the process of
heat-treatment HT1 described with reference to FIG. 16F may be
omitted.
As a method of controlling a threshold voltage Vth of the
transistor TR shown in FIG. 15, as described with reference to FIG.
16F, a method of injecting La atoms into the interface between the
interface layer 312 and the high-k dielectric film 314 may be used.
The lanthanum-containing film 324 may be used as a source of La
atoms to be injected into the interface between the interface layer
312 and the high-k dielectric film 314. La atoms may be supplied to
the interface between the interface layer 312 and the high-k
dielectric film 314 from the lanthanum-containing film 324 through
a diffusion process. La atoms present in the interface between the
interface layer 312 and the high-k dielectric film 314 may form a
dipole together with a constituent material, for example, SiO.sub.2
or SiON of the interface layer 312, and thus, the threshold voltage
Vth of the transistor TR may be changed.
Referring to FIG. 16G, after sequentially forming a second
metal-containing layer 326B and a gap-fill metal layer 328 on the
first metal-containing layer 326A, a planarizing process, for
example, a chemical mechanical polishing (CMP) process may be
performed until an upper surface of the interlayer insulating film
344 is exposed, and thus, the integrated circuit device 300 may be
formed.
The first metal-containing layer 326A, the second metal-containing
layer 326B, and the gap-fill metal layer 328 may constitute a gate
320G. The interface layer 312, the high-k dielectric film 314, the
lanthanum-containing film 324, and the gate 320G may constitute a
gate structure 320.
The second metal-containing layer 326B may control a work function
of the gate 320G together with the first metal-containing layer
326A. In an implementation, the second metal-containing layer 326B
may include TiAlC, TiAIN, TiAlCN, TiAl, TaAIC, TaAlN, TaAICN, TaAl,
or a combination of these materials. In an implementation, the
second metal-containing layer 326B may include at least one of Mo,
Pd, Ru, Pt, TiN, WN, TaN, Ir, TaC, RuN, and MoN. The second
metal-containing layer 326B may include a single layer or a
multilayered structure.
The first metal-containing layer 326A may include La atoms diffused
from the lanthanum-containing film 324. The La atoms injected to
the first metal-containing layer 326A may affect charge density in
the first metal-containing layer 326A, and accordingly, the
threshold voltage Vth of the gate 320G may be changed.
The gap-fill metal layer 328 may be formed to fill the remaining
gate space GS on the second metal-containing layer 326B. If there
is no remaining gate space GS on the second metal-containing layer
326B, the gap-fill metal layer 328 on the second metal-containing
layer 326B may not be formed. The gap-fill metal layer 328 may
include tungsten (W), a metal nitride, such as TiN and TaN,
aluminum (Al), a metal carbide, a metal silicide, a metal aluminum
carbide, a metal aluminum nitride, a metal silicon nitride, or a
combination of these materials.
The integrated circuit device 300 formed by the method described
with reference to FIGS. 16A through 16G may include La atoms in an
interface between the interface layer 312 and the high-k dielectric
film 314. Also, the first metal-containing layer 326A above the
interface may also include La atoms. Accordingly, a transistor TR
having a precisely controlled threshold voltage Vth may be
realized.
In an implementation, as described with reference to FIG. 16E, to
form the lanthanum-containing film 324, an ALD process using the
lanthanum compound of Formula 1 according to the embodiment may be
used as a precursor. In the ALD process for forming the
lanthanum-containing film 324, the lanthanum compound of Formula 1
may provide characteristics for a source compound of the ALD
process, e.g., a relatively low melting point, a relatively high
vapor pressure, transportability in a liquid state, ease of
vaporization, and excellent thermal stability. Accordingly, a
process of forming the lanthanum-containing film 324 may be easily
performed by using the lanthanum compound of Formula 1.
FIG. 17 illustrates an equivalent circuit diagram of an integrated
circuit device 400 according to another embodiment. In FIG. 17, an
equivalent circuit diagram of a vertical NAND (VNAND) flash memory
device having a vertical channel structure is depicted.
A memory cell array 410 may have a 3D structure. The memory cell
array 410 may include a plurality of cell strings CS11, CS12, CS21,
and CS22 that extend in a vertical direction. Each of the cell
strings CS11, CS12, CS21, and CS22 may include a ground selection
transistor GST, a plurality of memory cell transistors MC1, MC2, .
. . MCn-1, and MC8, and string selection transistors SST1 and SST2,
which are connected in series. In FIG. 17, and it is depicted as an
example that one ground selection transistor GST and two string
selection transistors SST1 and SST2 are connected to the plurality
of cell strings CS11, CS12, CS21, and CS22.
The string selection transistors SST1 and SST2 of each of the cell
strings CS11, CS12, CS21, and CS22 may be connected to
corresponding bit lines BL1 and BL2. Also, the string selection
transistors SST1 and SST2 of each of the cell strings CS11, CS12,
CS21, and CS22 may be connected to string selection lines SSL11,
SSL12, SSL21, and SSL22. The ground selection transistors GST of
the cell strings CS11, CS12, CS21, and CS22 may be connected by
ground selection lines GSL. A common source line CSL may be
connected to the ground selection transistor GST of each of the
cell strings CS11, CS12, CS21, and CS22.
The plurality of memory cell transistors MC1, MC2, . . . MCn-1, and
MC8 arranged at the same level may be connected to the same gate
lines WL1, WL2, . . . WLn-1, and WL8. For example, a first memory
cell transistor MC1 connected to the ground selection transistor
GST may be connected to first memory cell transistors MC1 of
adjacent columns through the gate line WL1.
The integrated circuit device 400 shown in FIG. 17 may include a
lanthanum-containing film obtained by using the lanthanum compound
of Formula 1 according to the embodiment.
FIG. 18 illustrates a diagram of an example integrated circuit
device including a lanthanum-containing film according to the
embodiment. FIG. 18 illustrates a cross-sectional view of a partial
configuration of an example non-volatile memory device 400A that
may constitute a memory cell array 410 of the example integrated
circuit device 400 of FIG. 17. In FIG. 18, the bit lines BL1 and
BL2 shown in FIG. 17 are omitted.
Referring to FIG. 18, the non-volatile memory device 400A may
include ground selection transistors GST1 and GST2, a plurality of
memory cell transistors MC1, MC2, . . . MCn-1, and MCn, and string
selection transistors SST1 and SST2, which are sequentially formed
on a substrate 402. An insulating layer 472 may be arranged between
each of the ground selection transistors GST1 and GST2, the
plurality of memory cell transistors MC1, MC2, . . . MCn-1, and
MCn, and the string selection transistors SST1 and SST2.
Detailed descriptions of the substrate 402 may be generally the
same as the substrate 302 described with reference to FIG. 15. A
channel layer 420 may vertically extend on a partial region of the
substrate 402. A plurality of control gate electrodes 432, 434, and
436 that constitute the plurality of memory cell transistors MC1,
MC2, . . . MCn-1, and MCn, the ground selection transistors GST1
and GST2, and the string selection transistors SST1 and SST2, may
be arranged along sidewalls of the channel layer 420.
A storage structure 440 may be interposed between the control gate
electrodes 432, 434, and 436 and the channel layer 420. The storage
structure 440 may continuously extend along surfaces of the control
gate electrode 432, 434, and 436. An inside of the channel layer
420 may be filled with a buried insulating film 421.
The storage structure 440 may include a lanthanum-containing film
448 that is obtained by using the lanthanum compound of Formula 1
according to the embodiment. In FIG. 18, a case that the storage
structure 440 includes a tunneling insulating layer 442, a charge
storage layer 444, a blocking insulating layer 446, and a
lanthanum-containing film 448 that are sequentially stacked on a
surface of the channel layer 420 is depicted. The storage structure
440 may function as a gate insulating film.
In an implementation, the tunneling insulating layer 442 may
include silicon oxide, the charge storage layer 444 may include
silicon nitride, the blocking insulating layer 446 may include
aluminum oxide, and the lanthanum-containing film 448 may include
La.sub.2O.sub.3.
Each of the plurality of memory cell transistors MC1, MC2, . . .
MCn-1, and MCn may include the control gate electrode 432 that may
be electrically connected to the storage structure 440. Each of the
ground selection transistors GST1 and GST2 may include the control
gate electrode 434 that may be electrically connected to the
storage structure 440. Each of the string selection transistors
SST1 and SST2 may include the control gate electrode 436 that may
be electrically connected to the storage structure 440.
Each of the control gate electrodes 432, 434, and 436 may include a
conductive barrier film that may be in contact with the
lanthanum-containing film 448 of the storage structure 440 and a
conductive film formed on the conductive barrier film. The
conductive film may include conductive polysilicon, a metal, a
metal silicide, or a combination of these materials. For example,
the conductive film may include titanium silicide, tantalum
silicide, tungsten silicide, cobalt silicide, or lanthanum
silicide.
A common source line 462 may be arranged on a source region 404
formed in an upper region of the substrate 402. The ground
selection transistors GST1 and GST2, the plurality of memory cell
transistors MC1, MC2, . . . MCn-1, and MCn, and the string
selection transistors SST1 and SST2 may be located between the
channel layer 420 and the common source line 462. Sidewalls of the
common source line 462 may be covered with insulating spacers
464.
In the non-volatile memory device 400A shown in FIG. 18, the
storage structure 440 may include a lanthanum-containing film 448
that is interposed between the blocking insulating layer 446 and
the control gate electrodes 432, 434, and 436. Thus, since the
storage structure 440 includes the lanthanum-containing film 448
that includes a high-k dielectric film, the reliability of the
non-volatile memory device 400A may be increased.
In the non-volatile memory device 400A shown in FIG. 18, the
lanthanum-containing film 448 included in the storage structure 440
may be formed via an ALD process using the lanthanum compound of
Formula 1 according to the embodiment.
In an implementation, the method described with reference to FIGS.
1 and 2 may be used to form the lanthanum-containing film 448.
In the ALD process for forming the lanthanum-containing film 448,
the lanthanum compound of Formula 1 according to the embodiment may
provide characteristics suitable for the source compound, e.g., a
relatively low melting point, a relatively high vapor pressure,
transportability in a liquid state, vaporization easiness, and
excellent thermal stability. Accordingly, a process of forming the
lanthanum-containing film 448 by using the lanthanum compound of
Formula 1 may be readily performed. Also, when the lanthanum
compound of Formula 1 according to the embodiment is supplied into
a hole having a relatively high aspect ratio to form the storage
structure 440 of the non-volatile memory device 400A, a uniform
step-coverage characteristic can be obtained along a depth
direction of the hole.
FIG. 19 illustrates a plan layout of main constituent elements of
an integrated circuit device 500 according to another
embodiment.
Referring to FIG. 19, the integrated circuit device 500 may include
a plurality of active regions AC defined by a device isolation film
512. The active regions AC may be repeatedly arranged in a
separated state from each other in X and Y directions, and may have
a shape extending in a slanting direction to have a long-axis in a
direction (a Q direction in FIG. 19) which is different from the X
and Y directions. The gate structure GS may extend in the X
direction across the active regions AC.
FIGS. 20A through 20G illustrate cross-sectional views of stages in
a method of manufacturing an integrated circuit device according to
another embodiment. An example method of forming the example
integrated circuit device 500 of FIG. 19 will be described with
reference to FIGS. 20A through 20G. In FIGS. 20A through 20G, main
constituent elements corresponding to a cross-section of a line
Y-Y' of FIG. 19 are depicted along process operations.
Referring to FIG. 20A, device isolation trenches T1 that define a
plurality of active regions AC may be formed on a substrate 502,
and device isolation films 512 that fills the device isolation
trenches T1 around the active regions AC are formed. A plurality of
source/drain regions SD are formed in the plurality of the active
regions AC. Details about the substrate 502 are generally the same
as the substrate 302 described with reference to FIG. 15.
A plurality of mask line patterns 514 are formed on the active
regions AC and the device isolation films 512. The mask line
patterns 514 are separated from each other and extend parallel to
each other in the X direction. The mask line patterns 514 may
include an oxide film, a nitride film, or a combination of these
materials. A plurality of gate trenches GT extending parallel to
each other in the X direction are formed by etching the active
regions AC and the device isolation films 512 by using the mask
line patterns 514 as etch masks.
Referring to FIG. 20B, a gate dielectric film 520 covering an inner
surface of each of the gate trenches GT is formed. The gate
dielectric film 520 may include a high-k dielectric film having a
dielectric constant greater than that of a silicon oxide film, a
silicon nitride film, a silicon oxynitride film, an
oxide/nitride/oxide (ONO) film, or a silicon oxide film. The high-k
dielectric film may include HfO.sub.2, Al.sub.2O.sub.3,
HfAlO.sub.3, Ta.sub.2O.sub.3, or TiO.sub.2. A thermal oxidation
process, an ALD process, or a combination of these processes may be
used to form the gate dielectric film 520.
Referring to FIG. 20C, a metal-containing liner 532 and a metal
film 534 that fill the gate trenches GT may be formed on a
resultant product of FIG. 20B. Afterwards, unnecessary portions of
the metal-containing liner 532 and the metal film 534 are removed
by an etch-back process to remain portions of the metal-containing
liner 532 and the metal film 534 that respectively fill lower parts
of the gate trenches GT, and thus, a plurality of gate lines 530
are formed. After the gate lines 530 are formed, upper surfaces of
the mask line patterns 514 may be exposed.
The metal-containing liner 532 may include TiN, and the metal film
534 may include W.
Referring to FIG. 20D, a lanthanum-containing film 540 covering
upper surfaces of the gate lines 530 may be formed by using the
lanthanum compound of Formula 1 according to the embodiment. In an
implementation, the lanthanum-containing film 540 may include a
La.sub.2O.sub.3 thin film or a LaON thin film. In an
implementation, the method described with reference to FIGS. 1 and
2 may be used to form the lanthanum-containing film 540.
In the ALD process for forming the lanthanum-containing film 540,
the lanthanum compound of Formula 1 according to the embodiment may
provide characteristics suitable for the source compound, e.g., a
relatively low melting point, a relatively high vapor pressure,
transportability in a liquid state, vaporization easiness, and
excellent thermal stability. Accordingly, a process of forming the
lanthanum-containing film 540 by using the lanthanum compound of
Formula 1 may be readily performed.
Referring to FIG. 20E, a resultant product in which the
lanthanum-containing film 540 is formed is heat-treated HT2 to
diffuse La atoms to the metal-containing liner 532 from the
lanthanum-containing film 540. Thus, a La-doped metal-containing
liner 542 is formed on a portion of an upper region of the
metal-containing liner 532. The La-doped metal-containing liner 542
may be used as a work function control layer. In an implementation,
the La-doped metal-containing liner 542 may include La-doped TiN
film. While the resultant product in which the lanthanum-containing
film 540 is formed is heat-treated La atoms may be diffused into an
upper portion 544 of the metal film 534.
The heat-treatment HT2 may be performed at, e.g., a temperature in
a range of about 400.degree. C. to about 600.degree. C. for about 5
minutes to about one hour. In an implementation, although the
heat-treatment HT2 may be omitted, La atoms may be diffused into
the portion of the upper region of the metal-containing liner 532
from the lanthanum-containing film 540, and thus, the La-doped
metal-containing liner 542 may be formed.
Referring to FIG. 20F, the lanthanum-containing film 540 (refer to
FIG. 20E) is removed.
Referring to FIG. 20G, an upper space of each of the gate trenches
GT is filled with an insulating capping pattern 570, and
afterwards, an upper surface of the substrate 502 is exposed by
removing unnecessary films remaining on the substrate 502.
By way of summation and review, techniques of forming
lanthanum-containing thin films having a high gap-fill
characteristic and a high step-coverage characteristic in a narrow
and deep space having a high aspect ratio may be considered.
The embodiments may provide a lanthanum compound, which is a liquid
at room temperature, and a method of forming a thin film and an
integrated circuit device by using the lanthanum compound.
The lanthanum compound according to an embodiment may have a
relatively low melting point, may be easily transported in a liquid
state, may be readily vaporized (since it has a relatively high
vapor pressure), and may be readily delivered. Thus, the lanthanum
compound has appropriate characteristics for a precursor for
forming a lanthanum-containing film in a deposition process, e.g.,
an ALD process or a CVD process, in which a source compound is
supplied in a vaporized state. For example, a lanthanum compound
(e.g., including an asymmetrical amidinate of the lanthanum
compound) according to an embodiment may cause or facilitate a
reaction at a relatively low temperature. For example, a
lanthanum-containing film may be readily formed at a relatively low
deposition temperature. Also, the lanthanum compound (e.g.,
including the asymmetrical amidinate) may have excellent surface
adsorption characteristics, and may be appropriately used in an ALD
process.
The embodiments may provide a lanthanum compound having appropriate
characteristics for use as a source compound for forming a
lanthanum-containing film.
The embodiments may provide a method of forming a thin film using a
lanthanum compound having appropriate characteristics for use as a
precursor required for forming a lanthanum-containing film.
The embodiments may provide a method of manufacturing an integrated
circuit device, the method including a process of forming the
lanthanum-containing film having a favorable step-coverage
characteristic.
Example embodiments have been disclosed herein, and although
specific terms are employed, they are used and are to be
interpreted in a generic and descriptive sense only and not for
purpose of limitation. In some instances, as would be apparent to
one of ordinary skill in the art as of the filing of the present
application, features, characteristics, and/or elements described
in connection with a particular embodiment may be used singly or in
combination with features, characteristics, and/or elements
described in connection with other embodiments unless otherwise
specifically indicated. Accordingly, it will be understood by those
of skill in the art that various changes in form and details may be
made without departing from the spirit and scope of the present
invention as set forth in the following claims.
* * * * *